Process for artificially ageing blocks

ABSTRACT

An apparatus for artificially aging blocks such as concrete blocks, vitrified bricks and natural stones, having the following features. An underlying surface, on which the blocks can be placed in such a way that their surface to be worked and the adjoining edges are exposed. Essentially freely movable distressing bodies for applying to the surface to be worked and the adjoining edges. A vibration device sets the blocks and the distressing bodies in motion in relation to one another in such a way that the distressing bodies act on the surface and the exposed edges of the blocks. A limiting device restricts the lateral or horizontal movement of the distressing bodies essentially to the surface of the blocks. A magnet for at least one of depositing and removing the distressing bodies. The height of the limiting device is reducible and/or the limiting device is displaceable in such a way that the magnet can be brought close to the surface of the blocks for the depositing and/or removal of the distressing bodies.

This application claims priority from German Patent Application Serial No. 10 2004 015 348.3 filed Oct. 2, 2004. FIELD OF THE INVENTION

The invention relates to apparatuses for artificially ageing blocks, in particular concrete blocks, vitrified bricks and natural stones.

The invention also relates to a limiting device for use in an apparatus for artificially ageing blocks.

BACKGROUND OF THE INVENTION

Blocks, for example paving elements, facade elements, sand-lime blocks, concrete blocks, bricks or vitrified bricks, natural stones and the like, are often subjected to subsequent treatment, irrespective of the nature of their material, in order in this way to lose their artificial appearance.

Particularly frequently, freshly produced, set concrete blocks, in particular concrete paving slabs, are subjected to such subsequent treatment, in the course of which the surfaces and/or the edges are distressed or broken, in order in this way to adapt the appearance to that of natural stones. For this purpose, the concrete blocks are introduced in relatively large numbers into a rotating drum, where they are “rumbled”, the surfaces and edges of the blocks striking against one another and the blocks treated in this way leaving the drum in an “aged” state. Such an apparatus is known from DE-A 29 22 393.

When concrete blocks are treated in a rotating drum, surfaces and edges which are not even visible, for example when the aged blocks are used in paving, are also worked. To this extent, energy and time are unnecessarily wasted. Furthermore, for shipping purposes it is necessary to arrange the concrete blocks which have been treated and have left the rotating drum in a regular arrangement on a pallet, which requires an inordinate amount of work and time.

The prior art discloses for the sorting of the blocks sorting installations which appropriately align the blocks and arrange them in pallet form. Such sorting installations cause high procurement and operating costs and also have a corresponding space requirement.

DE 36 21 276 C2 discloses a process in which concrete blocks are applied as a single layer in regular arrangement to an underlying surface in the form of a panel. Subsequently, the exposed surface and the adjoining exposed edges, or essentially only the edges, of the concrete blocks are distressed in an irregular manner by means of a vibrating striking or distressing device.

This process makes it possible to dispense with a subsequent sorting device, since the layer of blocks as they are produced is not changed. The distressing tools of the distressing device are arranged on a movable carriage, which takes them over the surfaces of the blocks, so that the free surfaces and the upper edges of the blocks are distressed in an irregular manner by the distressing tools.

However, a disadvantage of this process is that the blocks aged in this way look as though they have been artificially worked and not naturally aged. An ideal edge rupture of the blocks, as produced by the rumbling of the blocks in a rotating drum, is not obtained by using the process of the congeneric document.

EP 0 860 258 B2 discloses an apparatus and a process in which the blocks are arranged in one or two layers, preferably in the layer in which they are produced, between two elements, preferably plates. In this arrangement, the lower plate, on which the concrete blocks rest, is in operative connection with a vibration device. The vibration device is used to bring the blocks into movement, so that they are moved back and forth between the plates. As this happens, the blocks strike against one another and against the upper and lower plates, whereby the edges are broken on the upper side and underside. Furthermore, the upper sides and undersides of the blocks are distressed by the respectively assigned plates. The vertical side edges of the concrete blocks and the side faces are broken or distressed by the respectively adjacent concrete blocks.

It has been found in tests that the edge rupture is that much worse the larger the size of the block to be aged. This is a result of the fact that the distressing angle is all the more shallow the larger the size of the block lodged between the plates. The shallow distressing angle results in unfavorable rupture of the edges.

In a way analogous to the ageing process by means of the rotating drum, there is the disadvantage that surfaces and edges of the blocks which are possibly not visible are worked, resulting in energy and time being unnecessarily wasted. In addition, the necessary working time, in particular in the case of set concrete blocks, is high and the edge rupture is not ideal.

The general state of the art discloses an ageing process used by the construction materials company Gebhart & Söhne GmbH & Co. KG in which the blocks are applied to an underlying surface. Subsequently, essentially freely movable distressing bodies are applied to the surfaces of the blocks that are to be worked. The blocks and the distressing bodies are set in motion in relation to one another by a vibrating motion of the underlying surface in such a way that the distressing bodies act in a distressing manner on the surface and the adjoining, exposed edges of the blocks. This produces rapid and effective ageing of the surface of the blocks and the adjoining exposed edges. The intensity of the motion of the blocks and of the distressing bodies is dependent on the vibration and the number of distressing bodies and their weight. The distressing bodies are repelled upward from the surface of the blocks on which they rest. Due to the force of gravity, the distressing bodies subsequently fall back again onto the surface of the blocks and collide with them, or have an “ageing” effect on them. The blocks are distressed in an irregular manner by the random upward propulsion of the distressing bodies and likewise random falling back of the distressing bodies. This produces a visual appearance corresponding to that of a naturally aged block.

In one embodiment of this ageing process it is provided that the blocks are aged in the layer in which they are produced. The blocks may in this case be applied to the underlying surface, preferably in the form of a panel, as a single layer. After that, the distressing bodies are placed onto the surface of the blocks, the underlying surface subsequently being made to vibrate, or made to vibrate already before the distressing bodies are placed on. The ageing of an entire layer of blocks produced can consequently be carried out in a time- and energy-saving manner. The result thereby corresponds at least to the result of blocks aged in a drum.

Subsequent sorting of the blocks is not necessary in the case of the process of the construction materials company Gebhart & Söhne GmbH & Co. KG.

In one embodiment it is envisaged that the underlying surface on which the blocks are placed is provided with a surrounding border, by which the applied blocks are limited in their lateral movement. It is provided in this case that the surrounding border surrounds the blocks with play, so that the blocks can assume a distance from one another which permits the distressing bodies to act between two adjoining edges of the blocks and/or of one block and the surrounding border. It is provided in this case that the surrounding border rises up above the surface of the blocks in the vertical direction, so that a lateral limitation is formed for the distressing bodies. The lateral limitation thereby restricts the movement of the distressing bodies essentially to the surface of the blocks. After working, it is envisaged to remove the distressing bodies again from the surface of the blocks.

According to the process of the construction materials company Gebhart & Söhne GmbH & Co. KG, it is envisaged for the distressing bodies to be formed from hard metal, metal or steel, it being intended that the distressing bodies are lifted off the surface of the blocks magnetically. For this purpose it is envisaged to arrange a magnet above the surface of the blocks. The distance of the magnet from the surface of the blocks is in this case chosen such that the distressing bodies do not touch the magnet during the working of the surface of the blocks.

In tests it has now been found that the depositing and/or removal of the distressing bodies from the surface of the blocks according to the known process of the construction materials company Gebhart & Söhne GmbH & Co. KG is not satisfactory. The surrounding border, which restricts the movement of the blocks and, by corresponding elevation also the movement of the distressing bodies, must be of a certain height in order that the distressing bodies cannot be pushed over the surrounding border. The surrounding border prevents the magnet from being brought into place to lift off the distressing bodies, or the magnet must be of a correspondingly high power to compensate for this. Since important concerns with respect to ageing processes are, on the one hand, competitive prices and, on the other hand, time- and energy-saving ageing of the blocks, an effective solution must be found with regard to the depositing/removal of the distressing bodies.

SUMMARY OF THE INVENTION

The present invention is therefore based on the object of providing an apparatus for artificially ageing blocks which overcomes the aforementioned disadvantages of the prior art, in particular permits advantageous depositing and/or removal of essentially freely movable distressing bodies from the surface of the blocks, it being intended that the apparatus can be produced at low cost and can be used in a time- and energy-saving manner.

It can be ensured by the solutions according to the invention that the magnet can be brought close to the surface of the blocks to the desired extent for the depositing and/or removal of the distressing bodies. It is nevertheless ensured that, during the implementation of the ageing process, i.e. while the distressing bodies are acting on the surface of the blocks, the limiting device is of such a height to ensure that the distressing bodies are restricted in their movement, for instance onto the surface of the blocks, and are not pushed over the limiting device.

The invention consequently gets away from the previous idea of a rigid limiting device.

It is possible by the solutions according to the invention to use a magnet with a lower power, since the low power can be compensated by bringing the magnet closer to the surface of the blocks. Since the magnet represents a high cost factor for the apparatus as a whole, this provides clear advantages. In addition, the energy requirement of the magnet can in this way be significantly lowered. The solutions according to the invention permit rapid and reliable depositing and/or removal of the distressing bodies from the surface of the blocks. The fact that the magnet can have a lower power as a result of the solutions according to the invention means that the depositing of the distressing bodies is also more easily possible, since the force of attraction of the magnet on the distressing bodies can be overcome more easily for depositing the same.

According to the invention, it may also be provided that the limiting device is connected to the magnet directly or via further elements.

It has been found to be particularly suitable to connect the limiting device to the magnet. It may be provided in this case that the magnet and the limiting device are brought up to the surface of the blocks by means of a guiding device or a lifting device (for example a hydraulic device or the like). This allows the same guiding device that is provided for lifting off and/or placing the distressing bodies onto the surface to be used at the same time for positioning the limiting device in such a way that, during the ageing process, the distressing bodies are restricted with regard to their lateral or horizontal movement to the surface of the blocks. In a simple way, the magnet and the limiting device may be arranged such that it can be ensured that, in the position which the limiting device assumes during the ageing process, the distance between the surface of the blocks and the underside of the magnet is so great that the distressing bodies cannot touch the underside of the magnet.

For example, the limiting device may be arranged in such a way that the lower edge of the limiting device is positioned above the surface of the blocks. However, the distance between the surface of the blocks and the lower edge of the limiting device should not be greater than the diameter of the distressing bodies, in order to prevent the distressing bodies from escaping through the gap. In this case, an additional surrounding border which surrounds or encloses the block is necessary on the underlying surface, to restrict the lateral horizontal movement of the blocks.

In a particularly advantageous refinement of the solution according to the invention it is provided that the limiting device encloses at least an upper region of the blocks during the ageing process. In this way, on the one hand the limiting device prevents the distressing bodies from being able to leave the surface of the blocks laterally or horizontally and on the other hand the blocks are restricted by the limiting device with regard to their possible horizontal or lateral movement. A separate surrounding border of the blocks is consequently no longer necessary to perform this function. A further advantage is that the magnet, the limiting device and the surface of the blocks to be worked form an at least almost enclosed space during the ageing process. The dust and the like produced by the working of the blocks is consequently restricted essentially to this enclosed space. This has easily imaginable advantages both for the operator and for the entire working environment.

It is of advantage if the limiting device is telescopic. A telescopic capability of the limiting device allows it to be easily pushed together when the magnet is to be brought closer to the surface of the blocks for the depositing and/or removal of the distressing bodies.

The sequence of movements of the limiting device necessary for telescoping may be performed or assisted for example by a hydraulic device or an electric motor. It is particularly advantageous, however, if the limiting device can be telescoped without additional drive elements. In this case, it may be provided that the magnet with the limiting device fastened to it is lowered to such an extent that the lower edge of the limiting device touches the underlying surface on which the blocks are resting. In a simple embodiment, this lowering of the limiting device or of the magnet fastened to it is already adequate for the magnet to pick up the distressing bodies located on the surface as a result of its magnetic force. The “height” of the limiting device consequently does not have to be reduced.

In an advantageous embodiment, however, it is provided that the magnet, with the connected limiting device, is lowered further once the limiting device has contacted the underlying surface. On account of the telescopic capability of the limiting device or the possibility that the limiting device can be pushed together, the magnet can be brought up further to the surface of the blocks.

Instead of a telescopic capability of the limiting device, or as an alternative to it, it may also be provided that the magnet and the limiting device are displaceable in relation to each other, for example the connection of the magnets to the limiting device may take place by a tongue and groove guide. In this way too, it can be ensured that the magnet can be lowered further, although the limiting device is already resting with its lower edge on the underlying surface of the blocks.

In one possible embodiment of the invention, the limiting device may extend upward from the underlying surface to which the blocks have been applied, as provided according to the ageing process of the construction materials company Gebhart & Söhne GmbH & Co. KG. On the basis of the solution which provides, inter alia, that the height of the limiting device can be reduced, the magnet can be brought up to the surface of the blocks in the desired way for the removal or depositing of the distressing bodies. In this case, it may be provided that the limiting device is formed in two or more parts and these parts are pushed together by lowering of the magnet. Alternatively, other devices which push the parts of the limiting device together, so that the magnet can be correspondingly brought up to the surface of the blocks, may also be provided.

According to the invention, it may further be provided that the limiting device has a stop edge, which restricts the lateral or horizontal movement of the blocks to be worked, the stop edge having a recess in the region of the limiting device which encloses the edges of the blocks that are to be worked during the working of the blocks by the distressing bodies.

The inventor has recognized in a way that is not obvious that the edges of the blocks which form the surrounding border of a layer of blocks as produced, and which consequently are adjacent the limiting device during the ageing process, can scarcely be worked, or not worked at all, by the distressing bodies. The reason for this is that the distressing bodies require a certain free space to allow them to strike against the peripheral edges of the blocks, preferably laterally. This free space occurs on a random basis between two adjacent blocks on account of the predetermined lateral or horizontal movement. As tests have found, however, this does not apply to the edges of the blocks that are adjacent the limiting device. Since the blocks have a tendency to drift apart, the edges of the blocks which form the outer row of a layer in which they are produced usually lie directly against the limiting device or are at too small a distance, so that the distressing bodies do not have adequate space to allow them to act on these edges.

The stop edge of the limiting device then predetermines the lateral or horizontal movement of the blocks to be worked. Since the stop edge has a recess, increasing the inside diameter, in the region of the limiting device that is arranged at the height of the edges to be worked during the ageing of the blocks, the distressing bodies are no longer hindered by the limiting device from ageing the edges of the blocks that are facing the limiting device. The recess may be configured as desired, it having been found to be adequate to configure the recess in such a way that it corresponds to part of the diameter, preferably at least half the diameter, of the distressing bodies.

In principle, the stop edge may also be formed by a series of projections, protuberances or the like. All that is important in this respect is that the stop edge provides the blocks with less freedom of movement in the horizontal or lateral direction than is provided for the distressing bodies by the recess or generally by the limiting device.

Formation of the stop edge as a peripheral edge has been found to be particularly suitable, in order largely to prevent escape of dust and the like.

It is possible by the solution according to the invention to form the underlying surface on which the blocks are placed for ageing independently of the dimensions and the form of the blocks to be aged or of the layer of blocks to be aged in which they are produced. The underlying surface can consequently be universally used. All that is necessary is to adapt the limiting device to the form of the blocks or the form of a layer of blocks as produced.

It is of advantage if the free space that is available to the blocks for lateral movement is less than the minimum diameter of the distressing bodies.

This prevents the distressing bodies from being able to penetrate into the gap between two edges of two adjacent blocks.

The solution according to the invention is not restricted to the simultaneous ageing of a specific number of blocks or a layer of blocks. The term “apparatus for artificially ageing blocks” can likewise be understood as meaning that only a single block is aged or fed to the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantageous developments and refinements emerge from an exemplary embodiment of the invention presented in principle hereafter on the basis of the drawings, in which:

FIG. 1 shows a plan view of a layer of blocks as produced, during the ageing process;

FIG. 2 shows a side view of a layer of blocks as produced, which have been applied to an underlying surface, with a limiting device which is connected to a magnet and arranged above that;

FIG. 3 shows a representation according to FIG. 2, the limiting device having been lowered to carry out the ageing process, and enclosing an upper region of the blocks;

FIG. 4 shows a representation according to FIG. 2, the limiting device having been lowered onto the underlying surface and pushed together, in order that the magnet can pick up the distressing bodies;

FIG. 5 shows a view of the limiting device and of the magnet from below according to the direction of the arrow V of FIG. 2; and

FIG. 6 shows a representation of a detail of a stop edge of the limiting device in a representation during the implementation of the ageing process.

DETAILED DESCRIPTION OF THE INVENTION

According to the invention, any desired blocks, for example paving elements, facade elements, sand-lime blocks, concrete blocks, bricks or vitrified bricks or natural stones, can be aged, irrespective of the nature of their material. The ageing of blocks 1 which are formed as concrete blocks is presented below on the basis of the exemplary embodiment. However, it goes without saying that the invention is not restricted to this.

The production of concrete blocks 1, in particular of concrete paving slabs, is sufficiently known, for which reason it is not discussed in any more detail here. The concrete blocks 1 generally leave the production installation in a layer in which they are produced, i.e. in an arrangement in which a multiplicity of concrete blocks 1 are arranged next to one another as a single layer. Such a layer of blocks as produced is represented by way of example in FIGS. 1 to 4.

As can be seen from FIG. 1, the concrete blocks 1 are applied as a single layer to an underlying surface 2. The concrete blocks 1 are in this case arranged in such a way that the edges 1 b respectively to be worked, or the surface 1 a to be worked (=generally the side that will be visible later) of the block 1 lies at the top.

FIG. 1 shows a plurality of distressing bodies 3, which have been applied to or placed onto the surface 1 a of the blocks 1. The distressing bodies 3 are freely movable with respect to the surface 1 a. The distressing bodies 3 are likewise freely movable with respect to one another. In the exemplary embodiment, it is provided that the distressing bodies 3 are formed from hard metal, metal or steel. The form of the distressing bodies 3 may be chosen as desired, it having been found to be advantageous to form the distressing bodies 3 in a spherical, annular, polygonal or cylindrical manner. In the exemplary embodiment represented, the distressing bodies 3 are formed in a spherical manner.

A magnet 4 is provided in order to deposit the distressing bodies 3 onto the surface 1 a of the blocks 1 and remove them again from the latter. By appropriate magnetizing or demagnetizing of the magnet 4, the distressing bodies 3 are either attracted by the magnet 4 or fall from it (due to gravitational force) in the direction of the surface 1 a of the blocks 1.

Once the distressing bodies 3 are resting on the surface 1 a of the blocks 1, the vibration process, or the actual ageing process, begins. In an alternative embodiment, it may also be provided in this case that the vibration process is already in progress while the distressing bodies 3 are applied. FIG. 1 shows a possible representation or arrangement of the blocks 1 during the ageing process, i.e. during the vibration of the underlying surface 2. To produce the vibration, vibration devices 5, such as that represented for example in FIGS. 2, 3 or 4, may be used. The vibration devices 5 may be formed, for example, as unbalanced mass vibration generators. The blocks 1 and the distressing bodies 3 are set in motion in relation to one another by the vibration device 5 in such a way that the distressing bodies 3 act on the surface 1 a and the exposed edges 1 b of the blocks 1. The vibrating motion of the underlying surface 2 causes the distressing bodies 3 to be repelled from the surface 1 a of the blocks 1, in order subsequently to fall back again onto the surface 1 a or the edges 1 b. The lateral or horizontal movement of the distressing bodies 3 is thereby restricted essentially to the surface 1 a of the blocks 1. Provided for this purpose is a limiting device 6, which surrounds or encloses the distressing bodies 3 in such a way that the lateral or horizontal movement of the distressing bodies 3 is restricted essentially to the surface 1 a of the blocks 1.

In the exemplary embodiment, the limiting device 6 also serves for limiting the lateral or horizontal movement of the blocks 1. The limiting device 6 in this case encloses an entire layer of blocks 1 as produced. For this purpose, the limiting device 6 is positioned during the ageing process in such a way that the limiting device 6 encloses or surrounds at least an upper region of the blocks 1. The area enclosed by the limiting device 6 is in this case greater than the surface area which the blocks 1 take up when they are adjacently arranged. Consequently—as a result of the vibrating motion of the underlying surface 2—the blocks 1 have the possibility of assuming a distance from one another. This is represented in FIG. 1. For reasons of overall clarity, FIG. 1 does not show the limiting device 6, which encloses the upper region of the blocks 1 and the distressing bodies 3 during the ageing process according to FIG. 3.

The limiting device 6 makes it possible that the blocks 1 can assume a distance from one another which permits the distressing bodies 3 to act on two adjoining edges 1 b of two blocks 1 and/or of one block 1 and of the wall of the limiting device 6, without the distressing bodies 3 being able to penetrate completely into the intermediate spaces produced.

As can be seen from FIG. 6, the limiting device 6 has a peripheral stop edge 7, which restricts the lateral or horizontal movement of the blocks 1 to be worked. The stop edge 7 has in this case a recess 8. The recess 8 is arranged in such a way that it encloses the edges 1 b of the blocks 1 that are to be worked when the limiting device 6 has assumed the position intended for carrying out the ageing process. The recess 8 increases the inside diameter of the limiting device 6 in comparison with the inside diameter that is predetermined by the stop edge 7. In this way there is an increased inside diameter in the region of the edges 1 b to be worked, making it possible—even if the blocks 1 are lying against the stop edge 7—that the distressing bodies 3 can age or work the edges 1 b facing the limiting device 6.

The stop edge 7 may also be defined as an inwardly directed projection, which does not extend into the region of the upper edges 1 b, so that in this case too there is an increased inside diameter of the limiting device 6 in the region of the edges 1 b to be worked.

FIG. 6 shows, when considered together with FIG. 3, an at least almost enclosed space 9, within which the distressing bodies 3 can move for working the blocks 1. The space 9 is in this case bounded or formed by the magnet 4, the limiting device 6 and the upper side 1 a of the blocks 1 to be worked.

In the exemplary embodiment, the limiting device 6 is connected directly to the magnet 4. Alternatively, this may also take place via further elements. The magnet 4 and the limiting device 6 (considered together) are formed as a dish or cup. In the exemplary embodiment, the limiting device 6 is formed as a frame and is connected to the magnet 4 with one edge flush.

After the working of the surface 1 a and/or the edges 1 b of the blocks 1, the distressing bodies 3 are magnetically lifted off the surface 1 a. For this purpose, the magnet 4, and consequently also the limiting device 6, is connected to a movable guiding device 10, which can lower and raise the magnet 4/the limiting device 6. Many solutions for the configuration of the guiding device 10 are known from the general state of the art.

FIG. 2 shows a positioning of a layer of blocks 1 before the beginning of the ageing process.

FIG. 4 shows in this case the limiting device 6 and the magnet 4 in a view from below. The distressing bodies 3 are in this case located on the underside of the magnet 4 and are attracted by it. In order to begin the actual ageing process, the limiting device 6 is lowered together with the magnet 4 by the guiding device 10 until the limiting device 6 encloses an upper region of the blocks 1. This is represented in FIG. 3. After reaching this position, which is also represented in section in FIG. 6, the ageing process can begin. As a result of the vibration devices 5, the distressing bodies 3 are set in motion and repelled upward, so that subsequently, due to gravitational force, they fall back again onto the surface 1 a or the edges 1 b of the blocks 1 with distressing action. On account of the vibration, the blocks 1 move laterally or horizontally, so that the position represented in FIG. 1 is obtained.

After completion of the ageing process, the height of the limiting device 6 is reduced or the limiting device 6 is displaced in such a way that the magnet 4 can be brought close to the surface 1 a of the blocks for the removal of the distressing bodies 3. For this purpose, the limiting device 6 has a telescopic construction. In the exemplary embodiment, the limiting device 6 has two limiting parts 6 a, 6 b, which are vertically displaceable in relation to each other. In order to push the limiting parts 6 a, 6 b together, the limiting device 6 and the magnet 4 are lowered, until the lower edge of the limiting device 6 contacts the underlying surface 2. Further lowering then leads to the limiting parts 6 a, 6 b being displaced vertically in relation to each other, so that the height of the limiting device 6 is reduced and the magnet 4 is brought still further up to the surface 1 a of the blocks 1. This is represented in FIG. 4. Once the distressing bodies 3 have been drawn onto the underside of the magnet 4 and adhere there, the magnet 4 is raised again together with the limiting device 6. As a result, the limiting parts 6 a, 6 b move apart again. The aged layer of blocks 1 as produced can be removed and a new layer of blocks as produced can be fed in. In this way, the starting position represented in FIG. 2 is re-established. In the exemplary embodiment, the underlying surface 2 is formed as a conveyor belt. A vibration table or an underlying vibratory surface is arranged between the underlying surface 2 formed as a conveyor belt and the vibration devices 5.

In the exemplary embodiment it is provided that four vibration devices 5 are used, since in this way the amplitude of the vibration can be regulated in a simple way in dependence on the synchronicity of the vibration devices 5. In this case, the amplitude can, depending on synchronicity, assume any desired value between 0 and the maximum value.

For depositing the distressing bodies 3 onto the blocks 1, the magnetic force of the magnet 4 can be reduced in such a way that the distressing bodies 3 fall back onto the surface 1 a of the blocks 1 by their own weight or due to gravitational force.

In a particularly advantageous way, the apparatus according to the invention is also suitable for ageing split or cleaved blocks, which generally have an uneven surface or a surface provided with elevations and depressions. 

1-12. (canceled)
 13. An apparatus for artificially aging blocks, in particular concrete blocks, vitrified bricks and natural stones, with the following features: an underlying surface, on which the blocks can be placed in such a way that the surface of the blocks to be worked and the adjoining edges are exposed; essentially freely movable distressing bodies for applying to the surface to be worked and the adjoining edges; a vibration device, to set the blocks and the distressing bodies in motion in relation to one another in such a way that the distressing bodies act on the surface and the exposed edges of the blocks; a limiting device, which restricts the lateral or horizontal movement of the distressing bodies essentially to the surface of the blocks; a magnet for at least one of depositing and removing the distressing bodies, the height of the limiting device (6) being reducible and/or the limiting device (6) being displaceable in such a way that the magnet (4) can be brought close to the surface (1 a) of the blocks (1) for the depositing and/or removal of the distressing bodies (3).
 14. The apparatus as claimed in claim 13, wherein the limiting device (6) is connected to the magnet (4) one of directly and via at least one further element.
 15. The apparatus as claimed in claim 13, wherein the limiting device (6) encloses at least an upper region of the blocks (1) during the aging process.
 16. The apparatus as claimed in claim 13, wherein the magnet (4), the limiting device (6) and the upper side (1 a) of the blocks (1) to be worked forming an at least almost enclosed space (9) during the aging process.
 17. The apparatus as claimed in claim 13, wherein the limiting device (6) is telescopic.
 18. The apparatus as claimed in claim 13, wherein the limiting device (6) has at least two limiting parts (6 a, 6 b), which are vertically displaceable relative to one another.
 19. The apparatus as claimed in claim 13, wherein the limiting device (6) is able to be pushed together once a lower edge of the limiting device (6) contacts the underlying surface (2).
 20. The apparatus as claimed in claim 13, wherein the limiting device (6) has a stop edge (7), which restricts the lateral or horizontal movement of the blocks (1) to be worked, the stop edge (7) having a recess (8), increasing the inside diameter, in the region of the limiting device (6) which encloses the edges (1 b) of the blocks (1) that are to be worked during the working of the blocks (1) by the distressing bodies (3).
 21. The apparatus as claimed in claim 14, wherein the limiting device (6) is detachably connectable to the magnet (4).
 22. The apparatus as claimed in claim 13, wherein the limiting device (6) is formed as a frame.
 23. An apparatus for artificially aging blocks, in particular concrete blocks, vitrified bricks and natural stones, with the following features: an underlying surface, on which the blocks can be placed in such a way that their surface to be worked and the adjoining edges are exposed; essentially freely movable distressing bodies for applying to the surface to be worked and the adjoining edges; a vibration device, to set the blocks and the distressing bodies in motion in relation to one another in such a way that the distressing bodies act on the surface and the exposed edges of the blocks; a limiting device, which restricts the lateral or horizontal movement of the distressing bodies essentially to the surface of the blocks; a magnet for the depositing and/or removal of the distressing bodies, the limiting device (6) being connected to the magnet (4) directly or via further elements, the limiting device (6) and the magnet (4) being displaceable in relation to each other in the vertical direction.
 24. A limiting device for use in an apparatus for artificially aging blocks, in particular concrete blocks, vitrified bricks and natural stones with which essentially freely movable distressing bodies are used for working the surface and the adjoining edges of the blocks and a magnet is provided for the depositing and/or removal of the distressing bodies from the surface of the blocks, the limiting device restricting the lateral or horizontal movement of the distressing bodies essentially to the surface of the blocks, the limiting device (6) being able to be pushed together to reduce the height. 